Pub Date : 2021-08-06DOI: 10.47037/2020.aces.j.360623
Qiao Ren, Jimin Zhang, Jinnan Luo
This article designs an electromagnetic rotating eddy current brake (ECB), which has the advantages of no wear and low noise compared with traditional friction brake. First, using the magnetic circuit analysis model, a theoretical calculation formula of the ECB’s braking characteristics is given. The results show that the braking torque is negatively correlated with the thickness of the air gap as well as the electrical conductivity and the relative magnetic permeability of the brake disc material, and positively correlated with the number of ampere turns and the number of electromagnet poles. Secondly, a three-dimensional finite element (FE) model of the brake is established. The results of braking torque-speed characteristics between finite element calculation and theoretical analysis are compared, and the reasons for the differences between the two are explained. Using the FE model, the influence of the design parameters on torque characteristics is studied. Combined with the theoretical analysis model, the results are explained accordingly, providing a reference for the optimal design of the brake. Finally, a controller for the electromagnetic rotating eddy current brake is designed to control the amplitude of the desired braking torque.
{"title":"Characteristic Analysis and Control of a Rotary Electromagnetic Eddy Current Brake","authors":"Qiao Ren, Jimin Zhang, Jinnan Luo","doi":"10.47037/2020.aces.j.360623","DOIUrl":"https://doi.org/10.47037/2020.aces.j.360623","url":null,"abstract":"This article designs an electromagnetic rotating eddy current brake (ECB), which has the\u0000advantages of no wear and low noise compared with traditional friction brake. First, using the magnetic circuit analysis model, a theoretical calculation formula of the ECB’s braking characteristics is given. The results show that the braking torque is negatively correlated with the thickness of the air gap as well as the electrical conductivity and the relative magnetic permeability of the brake disc material, and positively correlated with\u0000the number of ampere turns and the number of electromagnet poles. Secondly, a three-dimensional finite element (FE) model of the brake is established. The results of braking torque-speed characteristics between finite element calculation and theoretical analysis are compared, and the reasons for the differences between the two are explained. Using the FE model, the influence of the design parameters on torque characteristics is studied. Combined with the theoretical analysis model, the results are explained accordingly, providing a reference for the optimal design of the brake. Finally, a controller for the electromagnetic rotating eddy current brake is designed to control the amplitude of the desired braking torque.","PeriodicalId":8207,"journal":{"name":"Applied Computational Electromagnetics Society Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84698574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-06DOI: 10.47037/2020.aces.j.360620
M. Ucar
In this paper, complementary split ring resonator (SRR) based reflector to enhance the printed slot dipole (PSD) antenna performance is introduced. The numerically calculated return-loss, directivity and radiation pattern results of the PSD antenna, with (w/) and without (w/o) CSRR element etched on reflector plane are presented and investigated. Numerical analysis and modelling of the proposed design are carried out using CST Microwave Studio simulator based on the finite integration technique. According to the simulation results, with the inclusion of the CSRR-based reflector into the PSD antenna, the directivity is increased by values changes from 0.6 dB to 4.25 dB through the operation band, while an improvement in bandwidth (~2.1%) is seen. It is also shown that this improvement in antenna performance is due to the -negative (ENG) behavior of CSRR structures. Prototype of the proposed antenna is fabricated using Arlon DiClad 880 substrate with electrical permittivity ofεr= 2.2. A quite good agreement between simulation and measurement is obtained. In this study, it is shown that the radiation performance of the antenna can be increased easily by using the CSRR element as a reflector in the antenna structure with a new enhancement approach. Also, the proposed antenna with a compact size of 0.27λ× 0.41λ is appropriate for operating in IEEE 802.11b/g/n/ax (2.4 GHz) WLAN applications.
{"title":"Complementary SRR-Based Reflector to Enhance Microstrip Antenna Performance","authors":"M. Ucar","doi":"10.47037/2020.aces.j.360620","DOIUrl":"https://doi.org/10.47037/2020.aces.j.360620","url":null,"abstract":"In this paper, complementary split ring resonator (SRR) based reflector to enhance the printed slot dipole (PSD) antenna performance is introduced. The numerically calculated return-loss, directivity and radiation pattern results of the PSD antenna, with (w/) and without (w/o) CSRR element etched on reflector plane are presented and investigated. Numerical analysis and modelling of the proposed design are carried out using CST Microwave Studio simulator based on the finite integration technique. According to the simulation results, with the inclusion of the CSRR-based reflector into the PSD antenna, the directivity is increased by values changes from 0.6 dB to 4.25 dB through the\u0000operation band, while an improvement in bandwidth (~2.1%) is seen. It is also shown that this improvement in antenna performance is due to the -negative (ENG) behavior of CSRR structures. Prototype of the proposed antenna is fabricated using Arlon DiClad 880 substrate with electrical permittivity ofεr= 2.2. A quite good agreement between simulation and measurement is obtained. In this study, it is shown that the radiation\u0000performance of the antenna can be increased easily by using the CSRR element as a reflector in the antenna structure with a new enhancement approach. Also, the proposed antenna with a compact size of 0.27λ× 0.41λ is appropriate for operating in IEEE 802.11b/g/n/ax (2.4 GHz) WLAN applications.","PeriodicalId":8207,"journal":{"name":"Applied Computational Electromagnetics Society Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89656435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-06DOI: 10.47037/2020.aces.j.360607
Zhengyong Yu, Li Baozhu, Shenggao Ding, Wanchun Tang
A compact dual-passband three-dimensional (3D) frequency selective surface (FSS) is proposed based on multiple square coaxial waveguides (SCWs), which exhibits good angular stability and both-side fast roll-off characteristics. The unit cell of the proposed 3D FSS is composed of one parallel plate waveguide (PPW) propagation path and two SCW propagation paths. By etching a centered annular slot, each SCW path forms two identical short SCWs. Each short SCW inherently generates one square slot resonance. In each SCW path, on the account of electromagnetic coupling between two square slot resonators provided by two short SCWs, the square slot resonant mode will split into even-/odd-resonant modes. Accordingly, each SCW path can provide a flat second-order passband with two transmission poles. Due to the reflection and out of phase of electromagnetic waves, four transmission zeros located at both sides of the passbands are introduced for high frequency selectivity, realizing both-side fast roll-off performances. In order to explain the operating principle, the electric-field distributions at transmission-zero/pole frequencies are investigated. Finally, an FSS prototype is fabricated and measured, and the results exhibit good angular stability for both TE and TM polarizations under incident angles from 0° to 60°. In addition, the proposed 3D FSS has a compact unit cell.
{"title":"Compact Dual-Passband Three-Dimensional FSS with Good Angular Stability and Both-Side Fast Roll-Off Characteristics","authors":"Zhengyong Yu, Li Baozhu, Shenggao Ding, Wanchun Tang","doi":"10.47037/2020.aces.j.360607","DOIUrl":"https://doi.org/10.47037/2020.aces.j.360607","url":null,"abstract":"A compact dual-passband three-dimensional (3D) frequency selective surface (FSS) is proposed based on multiple square coaxial waveguides (SCWs), which exhibits good angular stability and both-side fast roll-off characteristics. The unit cell of the proposed 3D FSS is composed of one parallel plate waveguide (PPW) propagation path and two SCW propagation paths. By etching a centered annular slot, each SCW path forms two identical short SCWs. Each short SCW inherently generates one square slot resonance. In each SCW path, on the account of electromagnetic coupling between two square slot resonators provided by two short SCWs, the square slot resonant mode will split into even-/odd-resonant modes. Accordingly, each SCW path can provide a flat second-order passband with two transmission poles. Due to the reflection and out of phase of electromagnetic waves, four transmission zeros located at both sides of the passbands are introduced for high frequency selectivity, realizing both-side fast roll-off performances. In order to explain the operating principle, the electric-field distributions at transmission-zero/pole frequencies are investigated. Finally, an FSS prototype is fabricated and measured, and the results exhibit good angular stability for both TE and TM polarizations under incident angles from 0° to 60°. In addition, the proposed 3D FSS\u0000has a compact unit cell.","PeriodicalId":8207,"journal":{"name":"Applied Computational Electromagnetics Society Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85678994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-06DOI: 10.47037/2020.aces.j.360624
Jeil Park, P. Gurrala, B. Hornbuckle, Jiming Song
We develop a method to model the microwave transmissivity of row crops that explicitly accounts for their periodic nature as well as multiple scattering. We hypothesize that this method could eventually be used to improve satellite retrieval of soil moisture and vegetation optical depth in agricultural regions. The method is characterized by unit cells terminated by periodic boundary conditions and Floquet port excitations solved using commercial software. Individual plants are represented by vertically oriented dielectric cylinders. We calculate canopy transmissivity, reflectivity, and loss in terms of S-parameters. We validate the model with analytical solutions and illustrate the effect of canopy scattering. Our simulation results are consistent with both simulated and measured data published in the literature.
{"title":"Modeling the Microwave Transmissivity of Row Crops","authors":"Jeil Park, P. Gurrala, B. Hornbuckle, Jiming Song","doi":"10.47037/2020.aces.j.360624","DOIUrl":"https://doi.org/10.47037/2020.aces.j.360624","url":null,"abstract":"We develop a method to model the microwave transmissivity of row crops that explicitly\u0000accounts for their periodic nature as well as multiple scattering. We hypothesize that this method could eventually be used to improve satellite retrieval of soil moisture and vegetation optical depth in agricultural regions. The method is characterized by unit cells\u0000terminated by periodic boundary conditions and Floquet port excitations solved using commercial software. Individual plants are represented by vertically oriented dielectric cylinders. We calculate canopy transmissivity, reflectivity, and loss in terms of S-parameters. We validate the model with analytical solutions and illustrate the effect of canopy scattering. Our simulation results are consistent with both simulated and measured data published in the literature.","PeriodicalId":8207,"journal":{"name":"Applied Computational Electromagnetics Society Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87889467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-06DOI: 10.47037/2020.aces.j.360619
Mohamed O. Khalifa, A. Yacoub, D. Aloi
In this paper, three Vehicular multiple-input multiple-output (MIMO) 5G antenna systems have been constructed from using a newly developed 5G cellular branched Monopole element are presented. The MIMO systems operates in the 5G frequency bands (617MHz- 5GHz) with a compact structure that allows for up to four elements to be integrated in the same Sharkfin. The 3 configurations of MIMO systems have been simulated using HFSS, measured on a 1-meter ground plane (GND), then measured on a vehicle roof and the individual antenna parameters in terms of reflection coefficient and efficiency have captured. The MIMO antenna systems performance in terms of passive isolation, combined radiation pattern, envelope correlation coefficient (ECC), and diversity gain (DG) have been reported and discussed.
{"title":"Compact 2x2 and 4x4 MIMO Antenna Systems for 5G Automotive Applications","authors":"Mohamed O. Khalifa, A. Yacoub, D. Aloi","doi":"10.47037/2020.aces.j.360619","DOIUrl":"https://doi.org/10.47037/2020.aces.j.360619","url":null,"abstract":"In this paper, three Vehicular multiple-input multiple-output (MIMO) 5G antenna systems have been constructed from using a newly developed 5G cellular branched Monopole element are presented. The MIMO systems operates in the 5G frequency bands (617MHz-\u00005GHz) with a compact structure that allows for up to four elements to be integrated in the same Sharkfin. The 3 configurations of MIMO systems have been simulated using HFSS, measured on a 1-meter ground plane (GND), then measured on a vehicle roof and the\u0000individual antenna parameters in terms of reflection coefficient and efficiency have captured. The MIMO antenna systems performance in terms of passive isolation, combined radiation pattern, envelope correlation coefficient (ECC), and diversity gain (DG) have been reported and discussed.","PeriodicalId":8207,"journal":{"name":"Applied Computational Electromagnetics Society Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90328798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-06DOI: 10.47037/2020.aces.j.360604
Jinbo Liu, Hongyang Chen, Hui Zhang, Jin Yuan, Zengrui Li
To efficiently analyze the electromagnetic scattering from composite perfect electric conductor (PEC)-dielectric objects with coexisting closed-open PEC junctions, a modified hybrid integral equation (HIE) is established as the surface integral equation (SIE) part of the volume surface integral equation (VSIE), which employs the combined field integral equation (CFIE) and the electric field integral equation (EFIE) on the closed and open PEC surfaces, respectively. Different from the traditional HIE modeled for the objects whose closed and open PEC surfaces are strictly separate, the modified HIE can be applied to the objects containing closed-open junctions. A matrix equation is obtained by using the Galerkin’s method of moments (MoM), which is augmented with the spherical harmonics expansion-based multilevel fast multipole algorithm (SE-MLFMA), improved by the mixed-potential representation and the triangle/tetrahedron-based grouping scheme. Because in the improved SE-MLFMA, the memory usage for storing the radiation patterns of basis functions is independent of the SIE type in the VSIE, it is highly appropriate for the fast solution of the VSIE that contains the HIE. Various numerical experiments demonstrate that during the calculation of composite objects containing closed-open PEC junctions, the application of the modified HIE in the VSIE can give reliable results with fast convergence speed.
{"title":"A Modified Hybrid Integral Equation to Electromagnetic Scattering from Composite PEC-Dielectric Objects Containing Closed-Open PEC Junctions","authors":"Jinbo Liu, Hongyang Chen, Hui Zhang, Jin Yuan, Zengrui Li","doi":"10.47037/2020.aces.j.360604","DOIUrl":"https://doi.org/10.47037/2020.aces.j.360604","url":null,"abstract":"To efficiently analyze the electromagnetic scattering from composite perfect electric conductor (PEC)-dielectric objects with coexisting closed-open PEC junctions, a modified hybrid integral equation (HIE) is established as the surface integral equation (SIE) part of the volume surface integral equation (VSIE), which employs the combined field integral equation (CFIE) and the electric field integral equation (EFIE) on the closed\u0000and open PEC surfaces, respectively. Different from the traditional HIE modeled for the objects whose closed and open PEC surfaces are strictly separate, the modified HIE can be applied to the objects containing closed-open junctions. A matrix equation is obtained by using the Galerkin’s method of moments (MoM), which is augmented with the spherical harmonics expansion-based multilevel fast multipole algorithm (SE-MLFMA), improved by the mixed-potential representation and the triangle/tetrahedron-based grouping scheme. Because in the improved SE-MLFMA, the memory usage for\u0000storing the radiation patterns of basis functions is independent of the SIE type in the VSIE, it is highly appropriate for the fast solution of the VSIE that contains the HIE. Various numerical experiments demonstrate that during the calculation of composite objects containing closed-open PEC junctions, the application of the modified HIE in the VSIE can give reliable results with fast convergence speed.","PeriodicalId":8207,"journal":{"name":"Applied Computational Electromagnetics Society Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75044579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-06DOI: 10.47037/2020.aces.j.360606
Somchat Sonasang, N. Angkawisittpan
A technique for directivity improvement of the microstrip parallel-coupled lines using symmetric-centered inductors is presented in this paper. The design procedure of the symmetric-centered inductors using the closed-form equations is given. The proposed technique was performed with a design at the operating frequency of 0.9 GHz on an FR4 substrate. Validity of the proposed technique is verified by simulations and measurements in comparisons with conventional parallel-coupled lines. The measured results exhibit the isolation of -30.10 dB and directivity of 19.28 dB at the operating frequency of 0.9 GHz. The directivity from the measured results is improved by more than 4 dB at 0.9 GHz and more than 6 dB at 1.05 GHz compared with the conventional parallel-coupled lines. In addition, the proposed technique for the microstrip parallel-coupled line can achieve a high directivity with the compact size (21.0 mm x 4.70 mm). The novelty of this paper is by introducing the proposed and closed-form design equations for the compact symmetric-centered inductors with high directivity.
提出了一种利用对称中心电感提高微带平行耦合线指向性的方法。给出了用封闭方程设计对称中心电感器的方法。该技术在FR4衬底上的工作频率为0.9 GHz。通过仿真和实测，与传统的平行耦合线进行了比较，验证了该技术的有效性。测量结果表明，在工作频率为0.9 GHz时，隔离度为-30.10 dB，指向性为19.28 dB。测量结果表明，与传统平行耦合线相比，在0.9 GHz和1.05 GHz频段的指向性分别提高了4 dB和6 dB以上。此外，所提出的微带平行耦合线技术可以实现高指向性和紧凑的尺寸(21.0 mm x 4.70 mm)。本文的新颖之处在于引入了高指向性紧致对称中心电感器的封闭设计方程。
{"title":"Design of Microstrip Parallel-Coupled Lines with High Directivity using Symmetric-Centered Inductors","authors":"Somchat Sonasang, N. Angkawisittpan","doi":"10.47037/2020.aces.j.360606","DOIUrl":"https://doi.org/10.47037/2020.aces.j.360606","url":null,"abstract":"A technique for directivity improvement of the microstrip parallel-coupled lines using symmetric-centered inductors is presented in this paper. The design procedure of the symmetric-centered inductors using the closed-form equations is given. The proposed technique was performed with a design at the operating frequency of 0.9 GHz on an FR4 substrate. Validity of the proposed technique is verified by simulations and measurements in comparisons with conventional parallel-coupled lines. The measured results exhibit the isolation of -30.10 dB and directivity of 19.28 dB at the operating frequency of 0.9 GHz. The directivity from the measured results is improved by more than 4 dB at 0.9 GHz and more than 6 dB at 1.05 GHz compared with the conventional parallel-coupled lines. In addition, the proposed technique for the microstrip parallel-coupled line can achieve a high directivity with the compact size (21.0 mm x 4.70 mm). The novelty of this paper is by introducing the proposed and closed-form design equations for the compact symmetric-centered inductors with high directivity.","PeriodicalId":8207,"journal":{"name":"Applied Computational Electromagnetics Society Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80324582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A three-layered transmitting focusing gradient meta-surface (FGMS) has been proposed, which can achieve broadband gain enhancement from 8.2 GHz to 10 GHz. The element of broadband transmitting FGMS has high transmitting efficiencies that over 0.7 and achieve [0, 2π] phase range with a flat and linear trend in the operating band. The FGMS can transform the spherical waves into plane waves. Three patch antennas working at 8.2 GHz, 9.1 GHz, and 10 GHz respectively are placed the focus of broadband FGMS as the spherical-wave source to build a broadband planar lens antenna system. It achieves a simulation gain of 15.44 dBi which is 7.51dB higher than that of the bare patch antenna at 10 GHz with satisfying SLLs and beamwidths. However, it enhanced the gain of the bare patch antenna in a wide operating band. Finally, the FGMS and the patch antenna are fabricated and measured. The measured results are in good agreement with the simulations.
{"title":"Gain Enhancement Planar Lens Antenna based on Wideband Focusing Gradient Meta-surface","authors":"Qiming Yu, Shaobin Liu, Zhengyu Huang, X. Kong, Huang Yuehong, Yongdiao Wen","doi":"10.47037/2020.aces.j.360605","DOIUrl":"https://doi.org/10.47037/2020.aces.j.360605","url":null,"abstract":"A three-layered transmitting focusing gradient meta-surface (FGMS) has been proposed, which can achieve broadband gain enhancement from 8.2 GHz to 10 GHz. The element of broadband transmitting FGMS has high transmitting efficiencies that over 0.7 and achieve [0, 2π] phase range with a flat and linear trend in the operating band. The FGMS can transform the spherical waves into plane waves. Three patch antennas working at 8.2 GHz, 9.1 GHz, and 10 GHz respectively are placed the focus of broadband FGMS as the spherical-wave source to build a broadband planar lens antenna system. It achieves a simulation gain of 15.44 dBi which is 7.51dB higher than that of the bare patch antenna at 10 GHz with satisfying SLLs and beamwidths. However, it enhanced the gain of the bare\u0000patch antenna in a wide operating band. Finally, the FGMS and the patch antenna are fabricated and measured. The measured results are in good agreement with the simulations.","PeriodicalId":8207,"journal":{"name":"Applied Computational Electromagnetics Society Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72390670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-06DOI: 10.47037/2020.aces.j.360622
Jin Enshu, Zhenyu Song, Y. Xiaofan, Yu Xin
The traditional Thevenin equivalent Modular Multilevel Converter (MMC) model has poor versatility for the two working conditions of pre-charging and DC-side faults. In this paper, an improved Thevenin equivalent MMC model considering pre-charge conditions and DC side fault conditions is proposed. The model divides the pre-charging condition into a Controllable charging stage and an Uncontrollable charging stage. The DC-side fault condition is divided into the pre-blocking and post-blocking conditions of the converter. The circuit characteristics are analyzed, and the equivalent model topology is comprehensively improved to make it suitable for full-condition simulation, and a control strategy suitable for the equivalent model is proposed. The detailed model and the proposed improved equivalent model were built in PSCAD/EMTDC for comparison and analysis. The simulation results shows that the improved equivalent model can be applied to various working conditions, and the versatility of the traditional Thevenin equivalent model is improved.
{"title":"Improved Thevenin Equivalent Model of MMC Considering Pre-charge Conditions and DC Side Fault Conditions","authors":"Jin Enshu, Zhenyu Song, Y. Xiaofan, Yu Xin","doi":"10.47037/2020.aces.j.360622","DOIUrl":"https://doi.org/10.47037/2020.aces.j.360622","url":null,"abstract":"The traditional Thevenin equivalent Modular Multilevel Converter (MMC) model has poor versatility for the two working conditions of pre-charging and DC-side faults. In this paper, an improved Thevenin equivalent MMC model considering pre-charge conditions and DC side fault conditions is proposed. The model divides the pre-charging condition into a Controllable charging stage and an Uncontrollable charging stage. The DC-side fault condition is divided into the pre-blocking and post-blocking conditions of the converter. The circuit characteristics are analyzed, and the equivalent model topology is comprehensively improved to make it suitable for full-condition simulation, and a control strategy suitable for the equivalent model is proposed. The detailed model and the proposed improved equivalent model were built in PSCAD/EMTDC for comparison and analysis. The simulation results shows that the improved equivalent model can be applied to various working conditions, and the versatility of the traditional Thevenin equivalent model is improved.","PeriodicalId":8207,"journal":{"name":"Applied Computational Electromagnetics Society Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81174806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-06DOI: 10.47037/2020.aces.j.360617
Rui Ma, Q. Feng
This paper presents a new coplanar waveguide (CPW)-fed circularly polarized square slot antenna (CPSSA). The proposed antenna uses an inverted Z-shaped feedline protruded from the signal line of the feeding CPW. Circularly polarized (CP) radiation can be achieved by adequately inserting the arc-shaped grounded strip into the upper right corner of the square slot. The widened vertical tuning stub on the L-shaped grounded strip can improve impedance matching and axial ratio (AR) performance. The measured results indicate that the 10 dB impedance bandwidth is 620 MHz (652-1272 MHz), and the 3 dB axial ratio bandwidth is 320 MHz (840-1160 MHz), which has a broadband characteristic. In the range of the universal UHF RFID band, the measured peak gain is about 4.4 dBi. The proposed CPSSA uses low-cost FR4 material as the dielectric substrate. The overall size of the antenna is 119 × 119 × 0.5 mm3. The proposed antenna has a simple structure, easy processing, good performance, wide operating bandwidth, and dual circular polarization characteristic. It can be applied to the universal UHF RFID handheld reader environment.
{"title":"Broadband CPW-Fed Circularly Polarized Square Slot Antenna for Universal UHF RFID Handheld Reader","authors":"Rui Ma, Q. Feng","doi":"10.47037/2020.aces.j.360617","DOIUrl":"https://doi.org/10.47037/2020.aces.j.360617","url":null,"abstract":"This paper presents a new coplanar waveguide (CPW)-fed circularly polarized square slot\u0000antenna (CPSSA). The proposed antenna uses an inverted Z-shaped feedline protruded from the signal line of the feeding CPW. Circularly polarized (CP) radiation can be achieved by adequately inserting the arc-shaped grounded strip into the upper right corner of the square slot. The widened vertical tuning stub on the L-shaped grounded strip can improve impedance matching and axial ratio (AR) performance. The measured results indicate that the 10 dB impedance bandwidth is 620 MHz (652-1272 MHz), and the 3 dB axial ratio bandwidth is 320 MHz (840-1160 MHz), which has a broadband characteristic. In the range of the universal UHF RFID band, the measured peak gain is about 4.4 dBi. The proposed CPSSA uses low-cost FR4 material as the dielectric substrate. The overall size of the antenna is 119 × 119 × 0.5 mm3. The proposed antenna has a simple structure, easy processing, good performance, wide operating bandwidth, and dual circular polarization characteristic. It can be applied to the universal UHF RFID handheld reader environment.","PeriodicalId":8207,"journal":{"name":"Applied Computational Electromagnetics Society Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83269235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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